.TH std::ranges::cend 3 "2024.06.10" "http://cppreference.com" "C++ Standard Libary"
.SH NAME
std::ranges::cend \- std::ranges::cend

.SH Synopsis
   Defined in header <ranges>
   Defined in header <iterator>
   inline namespace /* unspecified */ {

       inline constexpr /* unspecified */ cend = /*        \fI(since C++20)\fP
   unspecified */;                                         (customization point object)

   }
   Call signature
   template< class T >

       requires /* see below */                            \fI(since C++20)\fP

   constexpr /* see below */ auto cend( T&& t );

   Returns a sentinel
   for the constant iterator
   (since C++23) indicating the end of a
   const-qualified
   (until C++23) range.

   range-begin-end.svg

   Let CT be

     * const std::remove_reference_t<T>& if the argument is an lvalue (i.e. T is
       an lvalue reference type),                                                (until
     * const T otherwise.                                                        C++23)

   A call to ranges::cend is expression-equivalent to
   ranges::end(static_cast<CT&&>(t)).
   If the argument is an lvalue or
   ranges::enable_borrowed_range<std::remove_cv_t<T>> is true, then a call to
   ranges::cend is expression-equivalent to:

     * std::const_sentinel<decltype(U)>(U) for some expression U equivalent to   (since
       ranges::end(/*possibly-const-range*/(t)).                                 C++23)

   In all other cases, a call to ranges::cend is ill-formed, which can result in
   substitution failure when the call appears in the immediate context of a
   template instantiation.

   If ranges::cend(e) is valid for an expression e, where decltype((e)) is T, then
   CT models std::ranges::range, and
   (until C++23) std::sentinel_for<S, I> is true in all cases, where S is
   decltype(ranges::cend(e)), and I is decltype(ranges::cbegin(e)).
   Additionally, S models constant-iterator if it models input_iterator.
   (since C++23)

  Customization point objects

   The name ranges::cend denotes a customization point object, which is a const
   function object of a literal semiregular class type. For exposition purposes, the
   cv-unqualified version of its type is denoted as __cend_fn.

   All instances of __cend_fn are equal. The effects of invoking different instances of
   type __cend_fn on the same arguments are equivalent, regardless of whether the
   expression denoting the instance is an lvalue or rvalue, and is const-qualified or
   not (however, a volatile-qualified instance is not required to be invocable). Thus,
   ranges::cend can be copied freely and its copies can be used interchangeably.

   Given a set of types Args..., if std::declval<Args>()... meet the requirements for
   arguments to ranges::cend above, __cend_fn models

     * std::invocable<__cend_fn, Args...>,
     * std::invocable<const __cend_fn, Args...>,
     * std::invocable<__cend_fn&, Args...>, and
     * std::invocable<const __cend_fn&, Args...>.

   Otherwise, no function call operator of __cend_fn participates in overload
   resolution.

.SH Example


// Run this code

 #include <algorithm>
 #include <cassert>
 #include <ranges>
 #include <vector>

 int main()
 {
     std::vector vec{3, 1, 4};
     int arr[]{5, 10, 15};

     assert(std::ranges::find(vec, 5) == std::ranges::cend(vec));
     assert(std::ranges::find(arr, 5) != std::ranges::cend(arr));
 }

.SH See also

   ranges::end returns a sentinel indicating the end of a range
   (C++20)     (customization point object)
   end
   cend        returns an iterator to the end of a container or array
   \fI(C++11)\fP     \fI(function template)\fP
   \fI(C++14)\fP
